Building second-storey poured concrete floor

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Building second-storey poured concrete floor

Postby RY12 » Thu Nov 20, 2008 4:11 am

What are the structural and stability requirements for second-floor poured concrete floors? e.g. how far should the first-floor foundational posts be spaced, how much rebar needs to extend out of those posts or the horizontal beams into the floor? Does this rebar need to be welded or just tied? Is it going to be expensive to hire someone to build up the floor forms, and what are those forms- wood panels held up by bamboo or something?

I'm thinking of not walling in the first floor- so it would end up looking like a concrete Thai stilt house. I'm in Isaan and this will be a cheap little shed building, so NO cranes, cement trucks, cement hoses or anything.
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Re: Building second-storey poured concrete floor

Postby jazzman » Thu Nov 20, 2008 5:57 pm

Basically the upper storey beams are a repeat of the ground beam pattern, often 0.15 x 0.30 or 0.20 x 0.40 with the equivalent DB12 or DB16 rebar with 6mm stirrups placed every 20 cm. The columns will then be extensions of the existing columns below. It depends on what kind of floor and roof you will have. A light construction would be a wooden floor and a composite panel roof. A heavy construction would be a concrete floor and a roof covered with CPAC concrete tiles.

There is a lot of expensive and labour intensive formwork involved in upper storey ring beams, and the concrete must be laid in a contiguous pour so you'll either need ready-mix or two cement mixers and a chain gang to keep buckets of concrete coming.
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Re: Building second-storey poured concrete floor

Postby RY12 » Fri Nov 21, 2008 3:49 am

thanks jazzman (are you the only person on this forum? :lol: ). so in second-storey poured floors, I assume rebar extends out from the ring beams into the floor, but how far? also, how are columns and these horizontal ring beams tied together- are there big L-shaped pieces of rebar between the two? In the few pics I've seen of this process (any links to more would be great ), I don't recall seeing holes in the ring beam's wood forms for rebar to extend out of into the floor, so I'm confused. thanks
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Re: Building second-storey poured concrete floor

Postby jazzman » Fri Nov 21, 2008 9:37 am

No, I'm not the only one, but I'm probably one of the few who are mad enough to spend up to 18 hours a day working on a computer (when I'm not out on building sites) so I see most messages as soon as they get posted.
An upper storey concrete floor is not actually 'poured'. It made by by laying precast, pres-stressed concrete slabs across the tops of the Ring Beams - so there is no need to bend over the tops of the rebar. A thin coating of concrete is then poured over that to make it perfectly flat and ready for tiling; again another big action needing two cement mixers and a chain gang of women to pass buckets of mix up to the upper floor. But all this seems very ambitious for a 'cheap little shed'...

If you look at these two members' building stories, you might see some pictures of this system Apetly, CMX
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Re: Building second-storey poured concrete floor

Postby RY12 » Fri Jan 30, 2009 11:02 am

Hi Jazzman. I checked out those links and saw these pre-cast slabs you metioned here:

http://coolthaihouse.com/forum/download ... &mode=view

But they seem to be hoisted in by cranes... an expensive operation? I've talked to and seen on thaivisa many farangs who have built 1or 2-room one storey bungalow/guesthouses for 100-200k... I was hoping that for an extra 200k (400k total) I could get a similar house but raised up off the ground like the one on the left here:

http://www.crossy.co.uk/Thai_House_Plan ... /model.htm (but with not so many fancy windows or anything)

It would just be a small starter house, so no kitchen, cabinetry, or furniture, just 2 barebone rooms seperated by a bathroom. Reason I want it two stories is so we could build a kitchen in the future downstairs, and plus not take up so much space on our small lot. However I want to make sure I can get a relatively sound proof floor and ceiling to this place, since there's a noisy school nearby. But if it's prohibitively expensive to get pre-cast slabs onto a post-and-ring beam structure, then maybe I should stick with one storey.

Even if I could get these pre-cast slabs up on the second floor without a crane, is it still necessary to pour a reinforced concrete slab on top? or can I just smooth a 1-inch coat of cement on the slabs and just stick the tiles on that?

thanks :wink:
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Re: Building second-storey poured concrete floor

Postby thaifly » Fri Jan 30, 2009 11:54 am

RY12 wrote: But if it's prohibitively expensive to get pre-cast slabs onto a post-and-ring beam structure, then maybe I should stick with one storey.

Even if I could get these pre-cast slabs up on the second floor without a crane, is it still necessary to pour a reinforced concrete slab on top? or can I just smooth a 1-inch coat of cement on the slabs and just stick the tiles on that?

thanks :wink:
gidday..RY12..its the thaiflyfrommae rim...calmdown matey.....firstly its not a expensive operation ......the price of hoisting the slabs into place should be included in the price of the slabs...and naturally you will need some labour to help out in the operation..and you will be very surprised at the speeed of executing the slabs into place..providing the crane does nt give up the ghost whilst doing the job as was mine...and a layer of steelmesh has to be put intoplace ...followed by a layer of cement...and presto the job is done.. for tile or wooden floors... THERE WE GO THE GREAT JAZZMAN...is not the only one on the forum..but he sure does give us very good input on C.T.H..its a NO DRAMA GIDDAY TO ALL its the thaifly frommae rim
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Re: Building second-storey poured concrete floor

Postby jazzman » Fri Jan 30, 2009 12:04 pm

Hi,

If this is an extremely simple house, you can build it on pre-cast concrete 20 x 20 stilts instead of pouring them in situ. The crossy house in the picture uses concrete drainpipes filled with rebar and concrete.You can wall up the space below to make a ground-floor room.
You will save several thousand baht.
The Thais usually put a wooden floor on the upper storey, which although wood is relatively expensive, could also be a significant net saving. There will be no heavy elements to hoist up.

It is most unlikely that you will get the house in the picture built for only 200,000 baht - probably more in the region of 500,000, using low cost materials, surface wiring for the electrics, composite panels for the roof, and no Western style kitchens and bathrooms.
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Re: Building second-storey poured concrete floor

Postby RY12 » Fri Jan 30, 2009 12:45 pm

Thanks jazzman and thaifly!


jazzman wrote:If this is an extremely simple house, you can build it on pre-cast concrete 20 x 20 stilts instead of pouring them in situ. The crossy house in the picture uses concrete drainpipes filled with rebar and concrete.You can wall up the space below to make a ground-floor room.
You will save several thousand baht.
The Thais usually put a wooden floor on the upper storey, which although wood is relatively expensive, could also be a significant net saving. There will be no heavy elements to hoist up.

So if I got 6 20x20 precast stilts similar to the crossy pic, wouldn't I still need horizontal beams between them, i.e. a 'ring', to have the wooden planks rest on? The only thing I'm worried about with wood is that it won't be soundproof enough and I'd hear the noise of the schoolchildren and the city emanating through the floor... is this true? If not true, is it possible to tile on top of said wooden planks?

jazzman wrote:It is most unlikely that you will get the house in the picture built for only 200,000 baht - probably more in the region of 500,000, using low cost materials, surface wiring for the electrics, composite panels for the roof, and no Western style kitchens and bathrooms.

I was just referring to the 6-posted building with no groundfloor walls in the crossy pic, the one on the far left in the first pic. Yes, I actually am prepared to spend 500k, I had just hoped it would only be 400k since, like I said, other farangs have build 1 storey simple bungalows for 200k. Yes indeed, external wiring, tin or fiberglass roof, one toilet, 2 sliding-glass doors, a couple cheap doors for the bathroom, and a sink; nothing more. Can it be done? either with craned-up slabs on in situ posts, OR wood planks on precast stilts?

We're looking for builders now in Ubon, the other thing I'm worried about, if it is going to be 2-stories, that it be somewhat earth-quake proof. I'm worried we might end up picking a errant rice farmer contractor who cons us into thinking he can build a safe 2-stories... but it ends up being unstable. Then again, one contractor we talked to said 'no, no!' when we asked for 2-stories, she said it was too dangerous for her capabilities...
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Re: Building second-storey poured concrete floor

Postby jazzman » Fri Jan 30, 2009 6:16 pm

RY12 wrote:region of 500,000, using low cost materials, surface wiring for the electrics, composite panels for the roof, and no Western style kitchens and bathrooms.

I was just referring to the 6-posted building with no groundfloor walls in the crossy pic, the one on the far left in the first pic.[/quote]
In that case it should definitely cost you no more than 200,000, maybe even a lot less. You can do a concrete ring beam around the top of the pre-stressed posts, and lay your concrete slabs with 1" of cement on top. I've built a couple of gazeebos almost identical to this. Building time 3 - 4 weeks. Labour cost about 50,000 - 60,000.

Earthquakes? Someone's been pulling your leg :D
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Re: Building second-storey poured concrete floor

Postby RY12 » Sat Jan 31, 2009 12:38 am

Wow, thanks for the good news jazzman. :wink: would you happen to have an pics of these gazeebos?
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Re: Building second-storey poured concrete floor

Postby geordie » Sat Jan 31, 2009 4:18 am

Hello ry12 if youve not seen it done the preformed posts can seem a bit daunting i have just used them for speed in chayaphum
Basically when the posts are in situ the builder will set about the posts with a grinder exposing the rebar dependent on what you decide he will then either weld a steel frame to it or if in your case for a second floor he will attach the rebar for your second floor beams and posts
8 men were man handling 20x20 x 3.5 posts on site and erecting them vertically given this i would go for the concrete planks they will be no more than1/4-1/3 of the weight and give you as you say a bit better soundproofing also the floor if made from concrete is less apetising than wood
The planks are used bsically to save on shuttering which is unbelievebly expensive in thailand
as Thaifly stated the delivery usually includes the crane but even so the egyptians got by???
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Re: Building second-storey poured concrete floor

Postby thaifly » Sat Jan 31, 2009 11:06 am

geordie wrote:as Thaifly stated the delivery usually includes the crane but even so the egyptians got by???
its a gidday to ry12...its the thaifly from mae rim...with reference to my previous post on concrete slabs...i did a research on my picture C.D. taken during the course of building our project and found out some info which may help you to take this route instead of another alternative...i mentioned you may need some labour to help inputting the slabs into place ...on our job..that was not the case ...the supplier of the slabs threw in the driver of the crane plus 3 hands to put the slabs into place which was included the price of a slab ..which was from memory about 240 BAHT a slab.....personally i would put a layer of steel mesh on top of the slabs then pour your cement over it..to finish the job off nicely..then tile or lay a wooden floor...which ever you decide...we have taken this route on 5 of our buildings using the above method with tiles and wood..and to date it has been a success.....ITS A STEEL MESH GIDDAY TO ALL...ITS THE THAIFLY FROM MAE RIM
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Re: Building second-storey poured concrete floor

Postby jazzman » Sat Jan 31, 2009 1:17 pm

We have just started today building the bungalows on our land with 2.5 m preformed posts. If the design is right, they don't need grinding, they have an L-shaped notch in the top. Don't have the photos here in LOS, they were made in France before digital cameras. One was in the middle of one of my vinyard to give a great view over the nearby Rhône, and to stash some agricultural equipment under it. Another was for a friend in the Ardèche mountains. It was on a slope, the legs at the back were shorter than the ones on the front.
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Re: Building second-storey poured concrete floor

Postby RY12 » Sat Jan 31, 2009 1:39 pm

thaifly wrote:
geordie wrote:as Thaifly stated the delivery usually includes the crane but even so the egyptians got by???
the supplier of the slabs threw in the driver of the crane plus 3 hands to put the slabs into place which was included the price of a slab ..which was from memory about 240 BAHT a slab.....

Master thaifly, 240 baht a slab?! how big are they? the ones in the photo i linked to above looked to be maybe 3meters by 1meter... doesn't seem like they'd only be 240... maybe u meant 2,400? thanks
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Re: Building second-storey poured concrete floor

Postby geordie » Sat Jan 31, 2009 3:19 pm

oops some clarification
jazzman wrote:We have just started today building the bungalows on our land with 2.5 m preformed posts. If the design is right, they don't need grinding, they have an L-shaped notch in the top. Don't have the photos here in LOS, they were made in France before digital cameras.


The posts we used i am assuming are standard and had as above an l shaped notch in the top when we raised the posts there were some slight variations in heght of the posts something i was told not to worry
When the roofer kicked off he used a water level to mark all the posts and a 4" grinder to cut them all level
In doing this he exposed the rebar in the posts deliberatly so he could weld the steel wall plate to the top of the posts he did it with every post and the roof was built off this wall plate
When talking through my wife he said the same process was used with a second floor exposing the rebar would allow for tying the rebars for the ring beam on
This would be the case if we decided to add a second floor later
The l shaped notch is if you bolt on with timber (it has pre formed bolt holes) to the pre formed post it gives a good seat for the timber so the weight is not all supported on the
bolts and hopefully prevents the timber from splitting

and now for a shot to the foot ( somthing i am good at)

the planks i said earlier
geordie wrote:The planks are used bsically to save on shuttering which is unbelievebly expensive in thailand

The concrete planks i came across were only a couple of inches thick and a foot or so wide
on their own across a 3 mtr 4mtr span they would rely on the mesh and concrete poured onto them forming the floor binding the lot together giving it strength even with this method when you pour the concrete the floor will need good suport or its likely to bow and dip under the weight of the wet concrete
When this process is done then you would put the tiles or wood finish on top

somwhere on the site were fantastic pictures of the floor process i cannot remember who but it was a crawlspace under the house and planks were used same process as you want just lower

cruzing has pics of planks in use with a crawlspace but i am sure i have seen others
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